Generally, golf is a game in which users hit, by a club, a ball which is stationary and put on the course and insert the ball into prescribed holes, and the outcome thereof is concluded according to the number of hits made in the game. It is a general tendency that golf has become more popular as the sport can be enjoyed outdoors.
Because users can take advantage of training courses, which are close to home, for the training of golf, there is greater availability for golf training by the persons who are interested in golf or have trouble in getting to or having time to get to a golf course.
However, it is difficult for users to find time and go to golf training courses in order to adjust the posture of swing or a point of impact.
Consequently, there has been developed a lot of training machines for golf swing that user can correct easily his swing posture at home. Among the training machines for golf swing, one example titled “a training machine for golf swing” is disclosed in the Korean utility model registration No. 345643.
As disclosed, a traditional training machine for golf swing including a head portion 100 and a hollow body portion 200 comprises a fixing element 400 positioned on an end of the hollow body portion 200 toward the head portion 100; a movable element 600 positioned and freely movable within the hollow body portion 200; a spring 700 for connecting the movable element 600 to the hollow body portion 200 within the hollow body portion 200; and one end of the spring 700 is fixed to an end of the hollow body portion 200 toward the grip and the other end of the spring is connected to the movable element 600.
According to the traditional training machine for golf swing as constructed above, if a user grasps the grip and swings the golf club, the movable element 600 may be extended by the centrifugal force to overcome the resistance of the spring 700.
However, in the above-mentioned traditional training machine for golf swing, the centrifugal force that is initially generated at an initial stage of swing and increased gradually will be all reflected to the spring. In this case, if the speed of swing is fast, the movable element will collide with the fixing element well before a point of impact. Thus, an instant where the impact of the centrifugal force and the swing speed is maximized cannot be realized. In addition, when motion of swing is inadequately carried out due to a shake or weakness of the swing, the centrifugal force will not overcome the elastic force of spring to make the movable element to make contact to the fixing element.
Further, in order to make the moveable element overcome the elastic force of spring, a user should always swing a golf club with regular force regardless of the instant of impact that the centrifugal force and the swing speed are maximized. This may enable the user to correct his posture of swing regardless of the driver distance. However, it is impossible for the user to train the intensity of swing to conform to the distance desired by the hit of a ball. Furthermore, the precise impact cannot be realized because the user cannot identify the instant of impact of the hit that the centrifugal force and the swing speed are maximized due to the centrifugal force that is gradually increased from the initial stage of the swing.